Bioinformatics Analysis Reveals FOXM1/BUB1B Signaling Pathway as a Key Target of Neosetophomone B in Human Leukemic Cells: A Gene Network-Based Microarray Analysis

Shilpa Kuttikrishnan; Tariq Masoodi; Gulab Sher; Ajaz A Bhat; Kalyani Patil; Tamam El-Elimat; Nicholas H Oberlies; Cedric J Pearce; Mohmmad Haris; Aamir Ahmad; Feras Q Alali; Shahab Uddin

doi:10.3389/fonc.2022.929996

Bioinformatics Analysis Reveals FOXM1/BUB1B Signaling Pathway as a Key Target of Neosetophomone B in Human Leukemic Cells: A Gene Network-Based Microarray Analysis

Front Oncol. 2022 Jul 1:12:929996. doi: 10.3389/fonc.2022.929996. eCollection 2022.

Authors

Shilpa Kuttikrishnan^{1

2}, Tariq Masoodi³, Gulab Sher¹, Ajaz A Bhat³, Kalyani Patil¹, Tamam El-Elimat⁴, Nicholas H Oberlies⁵, Cedric J Pearce⁶, Mohmmad Haris^{3

7}, Aamir Ahmad^{1

8}, Feras Q Alali², Shahab Uddin^{1

7

8}

Affiliations

¹ Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar.
² College of Pharmacy, Qatar University, Doha, Qatar.
³ Laboratory of Molecular and Metabolic Imaging, Cancer Research Department, Sidra Medicine, Doha, Qatar.
⁴ Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan.
⁵ Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States.
⁶ Mycosynthetix, Inc., Hillsborough, NC, United States.
⁷ Laboratory of Animal Research Center, Qatar University, Doha, Qatar.
⁸ Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar.

Abstract

Abnormal expression of Forkhead box protein M1 (FOXM1) and serine/threonine kinase Budding uninhibited by benzimidazoles 1 (BUB1B) contributes to the development and progression of several cancers, including chronic myelogenous leukemia (CML). However, the molecular mechanism of the FOXM1/BUB1B regulatory network and the role of Neosetophomone-B (NSP-B) in leukemia remains unclear. NSP-B, a meroterpenoid fungal secondary metabolite, possesses anticancer potential in human leukemic cells lines; however, the underlying mechanism has not been elucidated. The present study aimed to explore the role of NSP-B on FOXM1/BUB1B signaling and the underlying molecular mechanism of apoptosis induction in leukemic cells. We performed gene expression profiling of NSP-B-treated and untreated leukemic cells to search for differentially expressed genes (DEGs). Interestingly BUB1B was found to be significantly downregulated (logFC -2.60, adjusted p = 0.001) in the treated cell line with the highest connectivity score among cancer genes. Analysis of TCGA data revealed overexpression of BUB1B compared to normal in most cancers and overexpression was associated with poor prognosis. BUB1B also showed a highly significant positive correlation with FOXM1 in all the TCGA cancer types. We used human leukemic cell lines (K562 and U937) as an in vitro study model to validate our findings. We found that NSP-B treatment of leukemic cells suppressed the expression of FOXM1 and BUB1B in a dose-dependent manner. In addition, NSP-B also resulted in the downregulation of FOXM1-regulated genes such as Aurora kinase A, Aurora kinase B, CDK4, and CDK6. Suppression of FOXM1 either by siRNA or NSP-B reduced BUB1B expression and enhanced cell survival inhibition and induction of apoptosis. Interestingly combination treatment of thiostrepton and NSP-B suppressed of cell viability and inducted apoptosis in leukemic cells via enhancing the activation of caspase-3 and caspase-8 compared with single-agent treatment. These results demonstrate the important role of the FOXM1/BUB1B pathway in leukemia and thus a potential therapeutic target.

Keywords: BUB1B; FOXM1; Neosetophomone B; TCGA; apoptosis; cell-cycle checkpoints; fungal metabolites; leukemia.